Composite sheet material



Nov. 27, 1951 J. ULANO I 2,576,491

COMPOSITE SHEET MATERIAL Filed May 21, 1948 FIGQI FIG. 2

FIG. 3 4 1 12 INVENTOR dseja/l 92-4770 BY AT'f'ORNEYS Patented Nov. 27,1951 UNITED STATES PATENT OFFICE.

COMPOSITE SHEET MATERIAL Joseph Ulano, Brooklyn, N. Y.

Application May 21, 1948, Serial No. 28,457

4 Claims. (Cl. Mil-128.2)

This invention relates to composite sheet material adapted especiallyfor use in processes in which apattern is produced by cutting outlinesof and removing a portion of the material.

One such process is known as silk screen printing, in which the patternis transferred to fabrics and the like 'by the application of apigmented vehicle through a silk screen to which the cutout sheetmaterial has been applied to form a kind of stencil. The pigmentedvehicle, passing only through that portion of the screen which is notcovered by the material, forms a pattern on the fabric corresponding tothe cutaway portion of the material. Another process is photographic,the image or pattern being transferred by the passage of light throughthe cutaway portion onto a photo-sensitive surface.

Heretofore; sheet material available for such uses has consisted of asheet of glassine or waxed paper (see Patent No. 1,781,834) as a backinghaving a layer of rubber composition and a superposed layer or film ofnitrocellulose lacquer. This may be produced by spraying or roll coatinga solution of the rubber composition on the paper and similarly applyinga solution of nitrocellulose lacquer upon the rubber coating.

In use, the composite sheet is placed over the design which is to bereproduced and the nitrocellulose film is cut with a sharp instrument inthe outline of the design. The cut-out portion of the nitrocellulosefilm is stripped, leaving the remainder of the nitrocellulose filmintact. The nitrocellulose film is then adhesively secured to a textilefabric, preferably silk, screen. Thereafter the paper backing isstripped and discarded.

A difliculty arises, however, because the paper is highly susceptible tochanges of relative humidity. It expands and contracts as much asthree-eighths of an inch in all-directions in the sizes ordinarily usedfor the purpose. Hence, if the cutting is started and thereafter, beforecom pletion, the relative humidity changes, the design will bedistorted. Even if the cutting is completed, the changes in dimension ofthe paper backing may distort the design before it is transferred to thesilk screen. Where more than one color is to be used, two or morescreens must be prepared, and distortion interferes with proper registryof the colors when the design is finally transferred to the fabric.Hence the paper backing as heretofore used is far from satisfactory, andsometimes unusable when relatively large designs are to be transferred.

It is the object of the present invention to provide a composite sheetmaterial which is free from the difliculties and disadvantageshereinbefore mentioned, and particularly one which is not susceptible tochanges in dimensions as the result of variation of relative humidity.

Other objects and advantages of the invention will be apparent as it isbetter understood by reference to the drawing, in which Fig. 1illustrates a design to be transferred, part of the design being red,for example, and the other green, for example. Of course, particularcolors employed have no relation to the present invention, since anycolors may be used.

Fig. 2 is a plan view of the sheet material with portions cut away toindicate the successive layers;

Fig. 3 is a plan view showing the application of the composite sheet tothe silk screen with a part of the design cut out;

Fig. 4 is a similar view showing the silk screen with the compositesheet applied thereto, and with the other portion of the design cut out;and

Fig. 5 is a side elevation of the composite sheet.

I have discovered that a very superior composite sheet material for thepurposes mentioned [and similar purposes may be prepared from a sheetconsisting of copolymers of a vinyl halide such as vinyl chloride and avinyl ester of an allphatic acid such as vinyl'acetate. Such sheetmaterial is available as a commercial product. It is a thin sheet havingan average thickness of .005 inch, flexible, transparent or translucentand of uniform quality. It is not susceptible to variations of relativehumidity and does not expand or contract under such variations. It isnot affected by solvents such as are used in preparing'a compositesheet. Hence it is particularly suited, as distinguished from otherplastic sheet material, for the purposes of the present invention.

As the backing sheet, I prefer a vinyl resin resulting from conjointpolymerization (by which is meant polymerization of two or morecompound-s while in mutual contact) of a vinyl halide such as vinylchloride and an oxygen-containing vinyl-compound such as the vinylesters of ali-' phatic acids, of which esters vinyl acetate is typical.The proportions of these substances in the original monomeric mixturemay be varied. I prefer a mixture containing parts of vinyl chloride to30 parts of vinyl acetate, but mixtures containing from '70 to parts ofvinyl chloride to 5 parts of vinyl acetate are generally suitable forthe purpose. The sheet material may be prepared from the pure resin bycalendering between hot rolls, or between heated, polished plates. Asindicated, such vinyl resins are not affected by moisture in theatmosphere and do not, therefore,

aerator nitrocellulose film in the subsequent application of the sheetmaterial.

Upon the rubber coating, I apply, by spraying. roll coating orotherwise, a layer or film 7 of nitrocellulose. The composition employedmay be varied, but I prefer to use one-half second and five secondsnitrocotton with pure castor oil as a plasticizer in a solventconsisting of a mixture of ethyl acetate, ethyl alcohol and petrolene.The viscosity of -the solution of nitrocellulose should be such as topermit the application in the manner indicated of a film abouttwothousandths of an inch in thickness. When the film. is dried byevaporation of the solvent, the composite sheet is complete and readyfor use.

In its application, a design consisting for example of the green portion9 and the red portion 9 is formed on a suitable sheet. The compositesheet is laid thereover, and the part to be reproduced in red it cutaway as indicated in Fig. 3. The sheet is then laid on the screen itwith the nitrocellulose film resting upon the fabric of the screen. Asuitable softener for the nitrocellulose film may be applied and thesheet rolled until adequate adhesion results. Thereupon the backingsheet is stripped, and the screen appears with the cutaway portion li sothat the pigmented vehicle may be applied to transfer the design tofabrics and the like.

Similarly, as shown in Fig. 4, the green portion 9 of the design asshown in Fig. 1 is traced with a sharp instrument, and thenitrocellulose film within the design is removed. Thereupon the sheet isreversed and placed upon the screen it, and the nitrocellulose film iscaused to adhere thereto in the manner previously indicated. Thereuponthe backing sheet 5 is stripped, leav= ing the screen 12 covered by thecellulose nitrate him, with the cutout design it thereon. By using thetwo screens successively with suitable pigmented vehicles, the design ofFig. 1 can be transferred to fabric and the like and, because the basematerial 5 has not been modified in dimensions, perfect registry betweenthe colors will be maintained. Of course, this is more important withcomplicated designs which are frequently transferred, in the mannerindicated, to fabrics.

No claim is made herein to the process of transferring designs, sincethat process has been in common use for many years.

The invention.

depends upon the use of the vinyl resin sheet material to avoid thedefects which exist in paper bacmngs heretofore employed in the manufacture of composite sheets for the purpose described.

Various changes may be made in the composite sheet as described withoutdeparting from the invention or sacrificing the advantages thereof.

1 claim:

1. A composite sheet for use in forming silk screen stencils including abacking sheet of vinyl resin comprising a. 'copolymer of a vinyl halideand a vinyl ester of an aliphatic acid, said backing sheet having anaverage thickness of about 0.005 inch and being dimensional stable inthe presence of moisture, a' cuttable stencil film, and a thin layer ofstrippable adhesive firmly securing the stencil film to the backingsheet.

2. A composite sheet as set forth in claim 1 in which the backing sheetcomprises a copolymer of vinyl chloride and vinyl acetate.

3. A composite sheet as set forth in claim 2 in which the backing sheetcomprises from to of vinyl chloride and 30% to 5% of vinyl acetate.

4. A composite sheet as set forth in claim 3 in which the adhesive isone having a rubber base and the stencil film is nitrocellulose.

JOSWH ULANO.

REFERENCES crrm The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name 1 Date 1,627,935 Stinchfield May 10,1927 1,781,834 DAutremont Nov. 13, 1930 1,829,618 Studer Oct. 27, 19312,028,712 Swan Jan. 21, 1936 2,028,936 Kratz et a1. Jan. 28, 19362,030,731 Young Feb. 11, 1936 2,038,118 McLaurin Apr. 21, 1936 2,047,957Fletcher July 21, 1936 2,099,154 Waters Nov. 16, 1937 2,234,06i Ulano eta1. Mar. 4, 1941 2,240,773 Harmon May 6, 1941 2,281,909 Barsky May 5,1942 2,302,817 Toland Nov. 24, 1942 2,311,889 Toland Feb. 23, 19432,312,623 Brooks et a1. Mar. 2, 1943 2,354,574 Carson- July 25, 19442,366,083 Box et a1. Dec. 26, 194% 2,414,320 Miller Jan. 14, 1947FOREIGN PATENTS Number Country Date 357,204 Great Britain of 1931 OTHERREFERENCES Vinylite Resins for Surface Coatings, published by BakeliteCorp. (1942). (Copy in Div. 67.)

1. A COMPOSITE SHEET FOR USE IN FORMING SILK SCREEN STENCILS INCLUDING ABACKING SHEET OF VINYL RESIN COMPRISING A COPOLYMER OF A VINYL HALIDEAND A VINYL ESTER OF AN ALIPHATIC ACID, SAID BACKING SHEET HAVING ANAVERAGE THICKNESS OF ABOUT 0.005 INCH AND BEING DIMENSIONAL STABLE INTHE PRESENCE OF MOISTURE, A CUTTABLE STENCIL FILM, AND